The present invention relates to cathode ray tubes and particularly to cathode ray tubes providing improved storage operation, improved storage target thereof and method of making such storage targets.
U.S. Pat. No. 3,531,675 discloses a cathode ray storage tube in which the storage target is provided with protrusions that have been etched from the insulating substrate and they and the surface from which they protrude are coated with a thin layer of transparent conductive metal oxide thereby defining a collector electrode. A dielectric layer is disposed onto this collector electrode and the other portions of the protusions extend outwardly beyond the dielectric layer. This storage target is expensive to manufacture due to the etching of the substrate to form the protrusions and the subsequent formation of the dielectric layer can vary in thickness at various locations over the target due to variance in the etching that takes place. The area of the protrusions also vary due to non-uniformities of the substrate and the fabrication thereof. The etched configuration of the substrate makes it difficult to discern non-uniformities and defects of the protrusions and dielectric layer. The operating areas of the protrusions can be impaired due to phosphor adhering too far up the protrusions thereby reducing the collection efficiency.